After a forever-long countdown to a three-tiered announcement, Valve has rolled out phase one of its plan to take over your living room: SteamOS.

What many thought was going to be a Steam Box console is for now in fact a Steam platform, one that will be available for hardware manufacturers to implement at will. Perhaps not surprisingly, the immediate focus is on gaming:

Finally, you don’t have to give up your favorite games, your online friends, and all the Steam features you love just to play on the big screen. SteamOS, running on any living room machine, will provide access to the best games and user-generated content available.

What's not entirely clear right now is what a "living room machine" entails; presumably one of Valve's two remaining announcements this week will rotate around its own device, as well as those by third-party manufacturers like last year's Piston Steam Box. Valve's remaining announcements will take place this Wednesday and Friday, respectively.

Why the need for SteamOS? Valve honcho Gabe Newell has long been saber-rattling in Windows 8's general direction, advocating instead for a Linux-based solution. Valve is wary of a Windows 8 that might threaten to supplant Steam as The Place To Go For Games. It's unlikely, but possible. Linux has proven to be a valuable escape route, but a flavor of Linux that is Steam just takes things a step further. There's no doubt that SteamOS is ultimately destined to be the elusive Steam Box's native language. Once that hits, Linux-compatibility (Valve must hope) becomes a whole new kind priority. It skews the question further from "does this support Linux?" and more towards "does this support Steam?" The former's a bonus, the latter less so.

SteamOS also stands to pull even non-gamers into the fold. SteamOS will heavily emphasize an AirPlay-like in-home streaming capability, an expanded focus on music, tv, and movies (read: non-gaming content, potentially including Spotify), and family sharing/parental controls. Or in other words, it will be a simple, free operating system that does just what you want your HTPC to do without all the confusing Linux bulk. No sudo apt-get here. And the more people Valve can get its hooks in, the more potential gamers will have Steam as their de-facto home for gaming if and when they decide to pick up a controller.

SteamOS will also focus on (naturally) graphics processing efficiencies, with access to the full 3000+ strong Steam catalog, and several top titles available—at some point—natively. Otherwise, all we know is that it'll be available "soon," and that the hardware's not far behind.[Valve]